New restrictions on using horses on roads in Romania have led to a surge in numbers of animals being put down

France has requested the government investigate two abattoirs which sold meat to European food companies, both outside Bucharest, one which sold only horses, another which sold both beef and horsemeat.

The Minister of Agriculture, Daniel Constantin, said it had checked records all the way back to the beginning of 2012 and he was confident the certification was in order, according to the BBC.

Constantin said that horse carcasses were easily distinguishable from beef - and the French processor which made the allegations about his country's meat producers had had no contact with either of the two Romania abattoirs.

"It is unacceptable as well to provide falsely labelled food and manipulate the British public of course as well."

The Environment Secretary Owen Paterson said on Monday that the horse meat scandal was the result of a criminal fraud conspiracy, on an "extensive" scale throughout Europe.

One theory for the apparent increase in the presence of horse meat in the food chain was new restrictions on using horses on roads in Romania, which have led to a surge in numbers of animals being put down.

Paterson said: "Reports today we have had from France looks as though it might have been pinned down to two abattoirs in Romania but I will be talking to authorities later in the day to establish that.

"I very much hope that these legal processes do flush out the criminals because it is completely unacceptable that British consumers should be sold a product marked as one thing which actually contains something else."

Last week Findus took its frozen beef lasagne, made by Comigel, off the shelves after some were found to have up to 100% horsemeat in them.